The present invention relates to power operated stock advancing apparatus of the type having a swingably mounted control arm for sensing the size of the stock loop and for actuating a speed control potentiometer to control operation of an electric drive motor. The stock advancing apparatus may comprise a stock reel that effects advance of the stock by winding or unwinding stock from a coil. The stock advancing apparatus can also comprise powered stock feed rollers or powered stock straightening rollers. In such power operated stock advancing apparatus it is desirable that the operating angle of the control arm be adjustable. In stock reels it is also desirable that they be adapted for operation with the control arm at either side of the reel, and that they be capable of either paying out or rewinding stock from either the top or bottom of the reel.
In prior stock reels known to the applicant, a lever on the control arm pivot shaft was arranged to operate the movable contact on a linear speed control potentiometer during rotation of the pivot shaft through a preselected angle. These prior art stock reels also had a manually operated control arm function switch and a manually operated control arm position switch for reversing the D.C. voltage applied to the potentiometer to adapt the stock reel for operation in either payout or rewind mode and also adapt the stock reel for operation with the control arm positioned on either side of the stock reel.
In these prior stock reels, the control arm was connected to the pivot shaft so that the control arm could be angularly adjusted relative to the shaft to change the operating angle of the control arm. However, it required considerable skill to change the operating angle by angularly adjusting the control arm relative to the pivot shaft. The operator had to apply a tool to the control arm pivot shaft; loosen the connection of the control arm to the pivot shaft; manipulate the tool to angularly position and hold the pivot shaft in the angular position at which the lever on the pivot shaft would position the movable contact on the potentiometer in a zero output voltage or null position; position and hold the control arm at the desired operating angle, and thereafter retighten the connection of the control arm to the shaft while holding both in the proper positions. Changing from the payout to rewind mode not only required operation of the payout-rewind switch, but also required readjusting of the angular position of the control arm relative to the pivot shaft since the zero output voltage position of the potentiometer in the rewind mode is different from that in the payout mode. In order to change the stock reel from operation with the control arm at one side of the reel to operation with the control arm at the other side of the reel, it was necessary to not only operate the manual control arm position switch, but to also disassemble the control arm from the pivot shaft and reassemble it with the control arm positioned at the other side of the stock reel, and to readjust the angular position of the control arm relative to the shaft in the manner previously described to a position that would be appropriate for operation at that side of the stock reel. A selectively operable motor rotation control switch was provided to enable reversing the direction of rotation of the drive motor, as required in different payout and rewind operation at different sides of the stock reel. The prior motor controls also commonly employed a manually adjustable potentiometer to adjust the percent of the maximum speed at which the reel would be driven in response to full output voltage from the speed control potentiometer, and some motor controls included a selectively adjustable acceleration control to adjust the rate of acceleration of the reel.